Plug for heat exchanger tubes

Abstract

A tube plug for sealing the end of a tube is provided, which includes a cylindrical housing member sized for insertion within the end portion of the tube. The housing member has a longitudinal blind bore comprising a smooth portion communicating with a threaded portion. An eccentric locking ring is mounted on the housing member for locking the inserted housing member against rotation relative to the tube. An insert member having a threaded end portion is received within the threaded portion of the bore. An enlarged portion is positioned to be drawn within the smooth portion of the bore in response to rotation of the insert member threaded end portion in the bore threaded portion. A tapered portion is provided between the end portion and the enlarged portion. The tapered portion is formed separately from the remainder of the insert member in the form of a truncated cone with a threaded bore therethrough for receiving the threaded end portion of the insert member. The enlarged portion has a recess therein for receiving a driving tool and for transmitting torque at levels greater than 450 inch pounds. The tapered portion and the enlarged portion are sized to cause the smooth portion of the bore to expand, thereby providing a seal between the housing member and the tube.

I claim as my invention: 
     
       1. A tube plug for sealing the end of a tube, comprising: a cylindrical housing member sized for insertion within the end portion of said tube, said housing member having a longitudinal blind bore comprising a smooth portion communicating with a threaded portion,     locking means mounted on said housing member for locking said inserted housing member against rotation relative to said tube, and   an insert member having a threaded end portion received within the threaded portion of said bore, an enlarged portion positioned to be drawn within said smooth portion of said bore in response to rotation of said insert member threaded end portion in said bore threaded portion, and a tapered portion between said threaded end portion and said enlarged portion, said enlarged portion having a recess therein for receiving a driving tool and for transmitting torque at levels greater than 450 inch pounds, and   said tapered portion and said enlarged portion being sized to cause said smooth portion of said bore to expand, thereby providing a seal between said housing member and said tube.     
     
     
       2. A tube plug according to claim 1, wherein said locking means comprises an eccentric ring rotatably mounted on a post projecting axially from an end of said housing member. 
     
     
       3. A tube plug according to claim 2, wherein said ring has a friction enhancing external cylindrical surface. 
     
     
       4. A tube plug according to claim 1, wherein said housing member has a friction enhancing outer surface. 
     
     
       5. A tube plug according to claim 1, wherein said insert member comprises a headed screw member and a separate frustoconical member which is threadingly received on said leaded screw member. 
     
     
       6. A tube plug according to claim 5, wherein said frustoconical member abuts against an underside of said head of said screw. 
     
     
       7. A tube plug according to claim 5, wherein said frustoconical member has an outer diameter at a larger end which is greater than a diameter of said screw head and said screw head is recessed within said frustoconical member. 
     
     
       8. A tube plug according to claim 2, wherein said ring is held on said post by means of a retaining ring received in an annular groove on said post. 
     
     
       9. A tube plug according to claim 1, wherein said lacking member includes a plurality of external annular grooves thereon surrounding said smooth bore portion. 
     
     
       10. A tube plug for sealing the end of a tube, comprising: a cylindrical housing member sized for insertion within the end portion of said tube, said housing member having a longitudinal blind bore comprising a smooth portion communicating with a threaded portion,     locking means mounted on said housing member for locking said inserted housing member against rotation relative to said tube, and   an insert member having a threaded end portion received within the threaded portion of said bore, an enlarged portion positioned to be drawn within said smooth portion of said bore in response to rotation of said insert member threaded end portion in said bore threaded portion, and a tapered portion between said threaded end portion and said enlarged portion, said tapered portion being formed separately from said threaded end portion and said enlarged portion of said insert member in the form of a truncated cone with a threaded bore therethrough for receiving said threaded end portion of said insert member, and   said tapered portion and said enlarged portion being sized to cause said smooth portion of said bore to expand, thereby providing a seal between said housing member and said tube.     
     
     
       11. A tube plug according to claim 10, wherein said locking means comprises an eccentric ring rotatably mounted on a post projecting axially from an end of said housing member. 
     
     
       12. A tube plug according to claim 11, wherein said ring has a friction enhancing external cylindrical surface. 
     
     
       13. A tube plug according to claim 10, wherein said housing member has a friction enhancing outer surface. 
     
     
       14. A tube plug according to claim 10, wherein said insert member comprises a headed screw member and said separate truncated cone abuts against a head of said headed screw member. 
     
     
       15. A tube plug according to claim 14, wherein said truncated cone abuts and terminates against an underside of said head of said screw member. 
     
     
       16. A tube plug according to claim 14, wherein said truncated cone has an outer diameter at a larger end which is greater than a diameter of said screw head and said screw head is recessed within said frustoconical member. 
     
     
       17. A tube plug according to claim 11, wherein said ring is held on said post by means of a retaining ring received in an annular groove on said post. 
     
     
       18. A tube plug according to claim 11, wherein said body includes a plurality of annular grooves thereon surrounding said smooth bore portion. 
     
     
       19. A tube plug according to claim 10, wherein said enlarged portion has a recess therein for receiving a driving tool and for transmitting torque at levels greater than 450 inch pounds. 
     
     
       20. A tube plug for sealing an end of a tube comprising: a body portion sized to be received within said tube with a minimum of clearance; said body portion having a friction enhancing outer surface and a central bore therein, with a portion of said bore having a smooth inner surface and a smaller radiused portion having an internal thread;     locking means comprising an eccentric ring rotatably mounted on a post projecting axially from an end of said body portion to prevent said body portion from rotating within said tube, said ring having a friction enhancing external cylindrical surface; and   an insert member comprising a headed screw having a threaded portion threadingly received within said threaded bore portion of said body portion and a separately formed tapered portion for engaging with said smooth bore portion of said body portion; said separately formed tapered portion comprising a frustoconical member with a threaded bore therethrough for engaging with said threaded portion of said insert member;   said insert member having a driving recess in an end thereof opposite said threaded portion for receiving a driving tool and for transmitting torque at a level above 450 inch pounds; and   said tapered portion and said enlarged portion being sized to cause said smooth portion of said bore to expand upon threaded insertion of said insert into said body portion, thereby providing a seal between said body portion and said tube.